1. Field of the Invention
The present invention generally relates to a camera and, more particularly, relates to a camera capable of properly operating when recovering from power interruption.
Also, the present invention relates to a camera and, more particularly, to a camera which has a disk-shaped code plate representing information inherent to a film in a film cartridge, and uses a film cartridge from which the leading end portion of a film is fed.
Furthermore, the present invention relates to a camera having a film feed controller and, more particularly, to a camera having a film feed controller which can use a film having two perforations per frame.
2. Description of the Related Art
In recent years, as a film to be loaded into a camera, a film cartridge which has an information recording disk which rotates integrally with a spool shaft in the film cartridge and which records information associated with a film as, for example, bar code information or the like, has been proposed. As a camera using such a film cartridge, various cameras, which read bar code information recorded on the information recording disk or the like upon initially feeding the film stored in the film cartridge, have been conventionally proposed.
For example, a film cartridge disclosed in U.S. Pat. No. 5,032,854 has an information recording disk which is rotatable integrally with a spool shaft arranged in the film cartridge, and records specific information associated with a film. In a camera using this film cartridge, when it is detected that the film cartridge is loaded into a camera main body, the spool shaft in the film cartridge is rotated by utilizing the rotation driving force of, e.g., a driving motor. Upon rotation of the spool shaft, the film, which is stored in the cartridge while being wound around the spool shaft, is externally fed from the film cartridge. In synchronism with the initial feeding operation of the film, information associated with the film and recorded on the information recording disk, i.e., information which corresponds to a DX code printed on the outer surface of a conventional film cartridge and is inherent to the film stored in the film cartridge, is read. Note that U.S. Pat. No. 5,032,854 above does not mention the details about processing of the read film information. Normally, information which is inherent to a film and read from the information recording disk, is stored in, e.g., a RAM (random access memory) in a control circuit (a microcomputer or the like) arranged in the camera and comprising, e.g., a CPU, and the information associated with the film is utilized in a photographing operation.
However, a battery or the like is used as the main power supply of the camera. Upon exchange of the battery when the power supply battery is used up, if a voltage drop takes place at the power supply terminal of the control circuit arranged in the camera main body and comprising, e.g., the CPU, the inherent information which is associated with the film loaded in the camera main body and stored in, e.g., the RAM of the control circuit, may be lost.
More specifically, according to means disclosed in U.S. Pat. No. 5,032,854, when a film is loaded into the camera main body, and is initially fed from the film cartridge, inherent information associated with the film is read from the information recording disk in the film cartridge in synchronism with this feeding operation, and is stored in, e.g., the RAM of the control circuit in the camera main body. At this time, when the power supply battery as the main power supply of the camera is exchanged, a voltage drop occurs at the power supply terminal of the control circuit, and the information associated with the film is lost.
Therefore, when the power supply battery as the main power supply of the camera is exchanged, the information associated with the film must be read again from the information recording disk in the film cartridge.
Furthermore, since the information recording disk rotates integrally with the spool shaft in the film cartridge, when the reading operation of information associated with the film is performed in a state wherein the film with unexposed frames is loaded in the camera main body, the film wound around the spool shaft is undesirably fed upon rotation of the spool shaft and the information recording disk in the film cartridge. At this time, in order to obtain continuously exposed frames on the film, the fed film portion must be rewound for several frames into the film cartridge, resulting in a complex operation sequence of the camera and an extra operation.
On the other hand, in recent years, various proposals associated with films and cameras have also been made. In these proposals, an information recording region is formed on a film, and photographing information is recorded on the information recording region, so that the information is utilized in correction, trimming, and editing operations, and the like in a print operation.
For example, Jpn. Pat. Appln. KOKAI Publication No. 4-136831 proposes a camera below. That is, when a battery is exchanged during a feeding operation of one frame of a film having one perforation per frame (one photographing frame) after a photographing operation of one frame, the film is moved after the exchange of the battery to detect the closest perforation, and a frame corresponding to the detected perforation is set at a photographing position.
A larger number of perforations are preferably formed in a film since a one-frame feeding operation, a rewind operation, and the like can be stabilized, and a stable operation free from an idle rotation or the like can be obtained. As for the number of perforations when an information recording region is formed on a film, two perforations can be formed per frame even when the information recording region is assured. In consideration of this fact, two perforations are preferably formed per frame since the operation can be stabilized.
However, Jpn. Pat. Appln. KOKAI Publication No. 4-136831 does not describe any method of feeding a film having two perforations per frame.
Furthermore, when a film having two perforations per frame is used in a film feed controller of the camera described in Jpn. Pat. Appln. KOKAI Publication No. 4-136831, the operation is performed as follows.
More specifically, after a photographing frame is exposed, a one-frame feeding operation is performed. (a) in FIG. 20 shows a photographing region and the positions of photographing frames with respect to perforation detection means immediately after a photographing frame Fa is exposed and before the feeding operation is started. In this state, the photographing frame Fa remains set at the photographing region. Photographing frames Fb, Fc, . . . are those to be set at the illustrated positions by the one-frame feeding operation after the photographing operation.
If a battery is removed due to any cause when the film moves to the position illustrated in (b) in FIG. 20, a state illustrated in (c) in FIG. 20 is set if the closest perforation is detected to set a photographing frame at the position of the photographing region. As a result, the photographing frame Fa is undesirably subjected to double exposure.
In this case, the subsequent photographing frames cannot be subjected to exposure at normal film positions. Furthermore, the correspondence between the photographing information recorded on a film and the photographing frames is disturbed.